The problem is that the effect of being in a pocket is not zero-biased when it comes to temperature (and possibly also humidity). You'd see temperatures being pulled towards normal body temperature on average.
Yes, but in my rudimentary understanding of weather the importance is the pressure differential rather than the absolute pressure.
I believe the data in aggregate will provide a pretty good map of the pressure gradient which could then be fixed to the more accurate dedicated weather stations. Think of it like the 10,000 year clock which uses a clock known to drift in conjunction with a solar time fix to calibrate.